Electrospinning Preparation And Performance Study Of Flexible Piezoelectric Nanogenerators

Flexible piezoelectric materials have a wide range of applications in the field of nanogenerator(NG),microscopic robotics,wearable and portable electronics on account of their advantages of flexibility,outstanding mechanical properties and output stability.Existing piezoelectric materials usually rely on secondary synthesis process to accomplish the preparation of conductive layer electrodes.However,these sandwich-structured piezoelectric nanogenerators(PENGs)with traditional layer electrodes suffer from drawbacks such as rigid,difficulty in miniaturization,disconnections between the functional materials and electrodes.Moreover,the secondary synthesis process of electrodes adds the cost,size and the manufacturing complexity of PENGs.There is an urgent need for flexible integrated materials to address the issue.In this thesis,we reported one-step strategy for synchronous construction of piezoelectric elements and nanoresistance networks.The[polyacrylonitrile]@[polyaniline/polyvinyl pyrrolidone] core-shell nanofibers(NFs)(denoted [PAN]@[PANI/PVP]),[PAN/BTO]@[PANI/PVP] core-shell NFs and PAN/PANI/PVP composite NFs have been successfully synthesized via electrospinning technology.The PAN/BTO(PAN)is used as functional elements and PANI/PVP is treated as nanoresistanc networks to realize the construction of flexible integrated piezoelectric nanomaterials.The characterization of the products was investigated in details by XRD,FTIR,SEM,TEM,EDS and TG-DSC.Three flexible PENGs were constructed through a simple encapsulation process.The output performance of the flexible PENGs was systematically studied and evaluated.The results reveal that three flexible PENGs without layer electrodes can directly result in a voltage signal under repeating press-release motions based on the Wheatstone bridge principle,which confirms the success of synchronous construction of piezoelectric elements and nanoresistance networks.Moreover,the integration of piezoelectric elements and nanoscale conductive networks enables the flexible PENGs to perform electromechanical conversion under low pressure down to approximately 0.05 N and a quick response,which indicates the superiority of flexible integrated nanofibers structure piezoelectric materials.It is expected to enable various applications in the field of micro/nano-scale wearable and portable electronics.To sum up,this thesis has designed and synthesized a series of flexible nanofiber materials that integrate piezoelectric materials and resistance networks,which realizes the synchronous construction of functional materials and conductive layers to overcome the limitation of electrodes on piezoelectric materials,as well as expand the functions of piezoelectric materials.What is more,this strategy has important meaning in reducing the size,the difficulty of the production process and the cost of flexible PENGs.It provides new idea and research foundation for the design and construction of flexible integrated energy conversion nanomaterials.